Electret Materials

ABSTRACT

Disclosed are electret materials with outstanding thermal and charge stability. The electret materials comprise a melt blend of a thermoplastic polymer and one or more compounds selected from the aromatic trisamides. The aromatic trisamides are for example of the formula 
     
       
         
         
             
             
         
       
     
     The melt blends are subjected to an electret treatment, for example a corona treatment. The electret materials are for example nonwoven polyolefin webs and are employed as filter materials, wipes, absorbent materials, filter masks, acoustic materials, printing substrates, measuring devices or contactless switches. The present electret materials may also comprise a further additive selected from the hindered amine light stabilizers and the hydroxyphenylalkylphosphonic esters or monoesters.

This application is a continuation of U.S. application Ser. No.13/151,732, which application is a continuation of U.S. application Ser.No. 12/079,605, filed Mar. 27, 2008, abandoned, which claims benefit ofU.S. provisional application Nos. 60/928,610, filed May 10, 2007 and60/922,024, filed Apr. 5, 2007, the contents of which are incorporatedherein by reference.

The present invention is aimed at electret materials having excellentthermal stability and charge stability. The electret materials are forexample polyolefin fibers or films and are suitably employed as filtermaterials, wipes, absorbent materials, filter masks, acoustic materials,printing substrates, measuring devices or contactless switches.

Background

U.S. Pat. No. 5,057,710 teaches electret materials comprising hinderedamines, nitrogen containing hindered phenols or metal-containinghindered phenols.

U.S. Pat. No. 5,556,618 discloses antibacterial electret materials.

U.S. Pat. No. 6,123,752 teaches high efficiency filter medium containinga performance enhancing additive.

U.S. Pat. No. 6,743,464 teaches a method of making electrets throughvapor condensation.

U.S. Pat. No. 6,969,484 discloses a method of making electret.

U.S. patent app. No. 60/791,047, filed Apr. 11, 2006, teaches electretmaterials comprising certain additives.

U.S. published app. No. 2005/0203226 and WO 2004/072168 teach trisamidenucleating agents.

Mohmeyer, et al., in Polymer, 48(2007), 1612-1619, discusses electretmaterials.

SUMMARY

Disclosed is an electret material with enhanced thermal and chargestability, which material has been subjected to an electret treatment,comprising

a thermoplastic polymer and

incorporated therein, an effective stabilizing amount of one or morearomatic trisamide compounds.

Also disclosed is a method for preparing an electret material withenhanced thermal and charge stability, which method comprises

melt blending a thermoplastic polymer with an effective stabilizingamount of one or more aromatic trisamide compounds and

subjecting the blend to an electret treatment.

DETAILED DISCLOSURE

The thermoplastic polymer is a non-conductive polymer that has thecapability of possessing a non-transitory or long-lived trapped charge.The polymer is for example a polyolefin, a halogenated vinyl polymer(e.g. polyvinyl chloride), polystyrene, polycarbonate, a polyester (e.g.polyethylene terephthalate), a polyamide or a fluoropolymer (e.g.polytetrafluoroethylene).

The thermoplastic polymers are for example propylene homopolymers,propylene copolymers and polypropylene blends. Propylene copolymers maycontain various proportions up to 90%, preferably up to 50%, ofcomonomers. Examples of comonomers are: olefins such as 1-olefins, e.g.ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene or 1-octene,isobutylene, cycloolefins, e.g. cyclopentene, cyclohexene, norbornene orethylidenenorborne, dienes such as butadiene, isoprene, 1,4-hexadiene,cyclopentadiene, dicyclopentadiene or norbornadiene; also acrylic acidderivatives and unsaturated carboxylic anhydrides such as maleicanhydride.

Polypropylene blends which can be used are mixtures of polypropylenewith polyolefins. Examples are blends of polypropylene with polyethyleneselected from the group consisting of high density polyethylene (HDPE),high molecular weight high density polyethylene (HMW HDPE), ultra highmolecular weight high density polyethylene (UHMW HDPE), medium densitypolyethylene (MDPE), low density polyethylene (LDPE), linear low densitypolyethylene (LLDPE), branched low density polyethylene (BLDPE) andethylene-propylene-diene terpolymers (EPDM) containing small proportionsof diene.

The polymer is especially a polyolefin, for example polypropylene,poly(4-methyl-1-pentene) or linear low density polyethylene, or blendsor copolymers thereof. The polymer may be a blend of a polyolefin and apolymer that contains polar groups, for example a polyester or apolyamide.

Polypropylene includes for instance reactor (such as metallocene) andvisbroken (e.g. peroxides, hydroxylamine esters, thermally broken, etc.)grades.

The electret material comprising the thermoplastic material is in theform of a nonwoven web, a film, or a woven fabric. The electret materialis in particular a nonwoven fibrous web.

The thermoplastic polymer may also be for example polyurethane or apolyester such as polylactic acid. The polyurethane may for example bein the form of a foam.

In addition to thermoplastic fibers, the electret material may be anatural fiber such as cotton.

The electret treatment may be any known treatment. Electret treatmentsare taught for example in U.S. Pat. Nos. 5,057,710, 5,556,618,6,123,752, 6,743,464, 6,969,484, 6,284,339, 5,256,176 and 6,926,961, thedisclosures of which are hereby incorporated by reference. The electrettreatment is for example hydro-charging, tribo-electric charging orcorona treatment. The electret treatment is especially a coronatreatment.

An electret material according to this invention is a thermoplasticmaterial that has been subjected to an electret treatment.

The aromatic trisamide compounds are taught for example in U.S.published app. No. 2005/0203226 and U.S. app. No. 10/544,508, publishedas WO 2004/072168, the contents of which are hereby incorporated byreference.

The aromatic trisamides are for instance of formula I

wherein

R₁, R₂, R₃, R₄, R₅ and R₆, independently of one another, are

hydrogen,

C₁-C₂₀alkyl,

C₂-C₂₀alkyl substituted by C₁-C₁₀alkylamino, di(C₁-C₁₀alkyl)amino,C₁-C₁₀alkyloxy or hydroxy;

C₃-C₂₀alkenyl,

C₅-C₁₂cycloalkyl,

C₅-C₁₂cycloalkyl substituted by 1, 2 or 3 C₁-C₁₀alkyl; cyclohexylmethyl;

cyclohexylmethyl substituted by 1, 2 or 3 C₁-C₁₀alkyl;

C₅-C₉cycloalkenyl,

C₅-C₉cycloalkenyl substituted by 1, 2 or 3 C₁-C₁₀alkyl;

phenyl substituted by 1, 2 or 3 radicals selected from the groupconsisting of C₁-C₁₀alkyl, C₁-C₁₀alkyloxy, hydroxy, halogen,trihalogenmethyl, trihalogenmethoxy, benzoyl, phenylamino, acylamino andphenylazo;

C₇-C₉phenylalkyl,

C₇-C₉phenylalkyl which is substituted on the phenyl by 1, 2 or 3radicals selected from the group consisting of C₁-C₁₀alkyl, C₁-C₁₀alkoxyand hydroxy;

naphthyl,

naphthyl substituted by C₁-C₁₀alkyl;

adamantyl, or

a 5 to 6 membered heterocyclic group.

Examples of C₁-C₂₀alkyl are methyl, ethyl, propyl, isopropyl, n-butyl,sec-butyl, isobutyl, tert-butyl, 2-ethylbutyl, n-pentyl, isopentyl,1-methyl pentyl, 1,3-dimethylbutyl, n-hexyl, 1-methyl-hexyl, n-heptyl,isoheptyl, 1,1,3,3-tetramethylbutyl, 1-methylheptyl, 3-methylheptyl,n-octyl, 2-ethylhexyl, 1,1,3-trimethylhexyl, 1,1,3,3-tetramethylpentyl,nonyl, decyl, undecyl, 1-methyl-undecyl, dodecyl,1,1,3,3,5,5-hexamethylhexyl, tridecyl, tetradecyl, pentadecyl,hexadecyl, heptadecyl, octadecyl and eicosyl. Preferred examples arebutyl, octyl and octadecyl.

Examples of C₂-C₂₀alkyl substituted by C₁-C₁₀alkylamino,di(C₁-C₁₀alkyl)amino, C₁-C₁₀alkyloxy or hydroxy are 3-methylaminopropyl,2-dimethylaminoethyl, 2-diethylaminoethyl, 3-dimethylaminopropyl,3-diethylaminopropyl, 2-methoxyethyl, 2-ethoxyethyl, 2-methoxypropyl,3-methoxypropyl, 2-ethoxypropyl, 3-isopropoxypropyl and hydroxyethyl.Preferred examples are 3-dimethylaminopropyl, 3-methoxypropyl and2-methoxyethyl.

Examples of C₃-C₂₀alkenyl are allyl, 2-methallyl, butenyl, pentenyl,hexenyl and oleyl. The carbon atom in position 1 is preferablysaturated. Preferred examples are allyl and oleyl.

Examples of C₅-C₁₂cycloalkyl are cyclopentyl, cyclohexyl, cycloheptyl,cyclooctyl and cyclododecyl. Preferred examples are cyclohexyl,cycloheptyl, cyclooctyl and cyclododecyl.

Preferred examples of C₅-C_(u)cycloalkyl substituted by 1, 2 or 3C₁-C₁₀alkyl are 3-methylcyclohexyl and 2,3-dimethylcyclohexyl.

An example of cyclohexylmethyl substituted by 1, 2 or 3 C₁-C₁₀alkyl is1-cyclohexylethyl.

An example of C₅-C₉cycloalkenyl is cyclohexenyl.

An example of C₅-C₉cycloalkenyl substituted by 1, 2 or 3 C₁-C₁₀alkyl ismethylcyclohexenyl.

Examples of phenyl substituted by 1, 2 or 3 radicals selected from thegroup consisting of C₁-C₁₀alkyl, C₁-C₁₀alkyloxy, hydroxy, halogen,trihalogenmethyl, trihalogenmethoxy, benzoyl, phenylamino, acylamino andphenylazo are 4-methylphenyl, 2-ethylphenyl, 4-ethylphenyl,4-isopropylphenyl, 4-tert-butylphenyl, 4-sec-butylphenyl,4-isobutylphenyl, 3,5-dimethyl phenyl, 3,4-dimethylphenyl,2,4-dimethylphenyl, 2,6-diethylphenyl, 2-ethyl-6-methylphenyl,2,6-diisopropylphenyl, 4-methoxyphenyl, 4-ethoxyphenyl, 4-hydroxyphenyl,4-fluorophenyl, 3,5-difluorophenyl, 2-chlorophenyl, 3-chlorophenyl,3-chloro-6-methylphenyl, 3,5-di(trifluoromethyl)phenyl,4-trifluoromethoxyphenyl, 2-benzoylphenyl, 4-phenylaminophenyl,4-acetamidophenyl and 4-(phenylazo)phenyl. A preferred example is3,4-dimethylphenyl.

Examples of C₇-C₉phenylalkyl are benzyl and 2-phenylethyl. Benzyl ispreferred.

Examples of C₇-C₉phenylalkyl which is substituted on the phenyl by 1, 2or 3 radicals selected from the group consisting of C₁-C₁₀alkyl,C₁-C₁₀alkoxy and hydroxy are methylbenzyl, dimethyl benzyl,trimethylbenzyl, tert-butylbenzyl, methoxybenzyl and3,5-di-tert-butyl-4-hydroxybenzyl.

An example of naphthyl substituted by C₁-C₁₀alkyl is methylnaphthyl.

Examples of a 5 to 6 membered heterocyclic group are 2-picolyl,(2-furyl)methyl, (2-tetrahydrofuryl)methyl, 2-pyrimidyl,6-methyl-2-pyridyl, 1,2,4-triazol-3-yl and 2-(1-piperazinyl)ethyl.

The aromatic trisamides are for example of formulae IIa, IIb or IIc

wherein

R₁, R₂ and R₃, or Y₁, Y₂ and Y₃, or Z₁, Z₂ and Z₃ independently of oneanother are C₁-C₂₀alkyl unsubstituted or substituted by one or morehydroxy;

C₂-C₂₀alkenyl unsubstituted or substituted by one or more hydroxy;

C₂-C₂₀alkyl interrupted by oxygen or sulfur;

C₃-C₁₂cycloalkyl unsubstituted or substituted by one or moreC₁-C₂₀alkyl;

(C₃-C₁₂cycloalkyl)-C₁-C₁₀alkyl unsubstituted or substituted by one ormore C_(l)-C₂₀alkyl;

bis[C₃-C₁₂cycloalkyl]-C₁-C₁₀alkyl unsubstituted or substituted by one ormore C₁-C₂₀alkyl;

a bicyclic or tricyclic hydrocarbon radical with 5 to 20 carbon atomsunsubstituted or substituted by one or more C₁-C₂₀alkyl;

phenyl unsubstituted or substituted by one or more radicals selectedfrom C₁-C₂₀alkyl, C₁-C₂₀alkoxy, C₁-C₂₀alkylamino, di(C₁-C₂₀alkyl)amino,hydroxy and nitro;

phenyl-C₁-C₂₀alkyl unsubstituted or substituted by one or more radicalsselected from C₁-C₂₀alkyl, C₃-C_(u)cycloalkyl, phenyl, C₁-C₂₀alkoxy andhydroxy;

phenylethenyl unsubstituted or substituted by one or more C₁-C₂₀alkyl;

biphenyl-(C₁-C₁₀alkyl) unsubstituted or substituted by one or moreC₁-C₂₀alkyl;

naphthyl unsubstituted or substituted by one or more C₁-C₂₀alkyl;

naphthyl-C₁-C₂₀alkyl unsubstituted or substituted by one or moreC₁-C₂₀alkyl;

naphthoxymethyl unsubstituted or substituted by one or more C₁-C₂₀alkyl;

biphenylenyl, flourenyl, anthryl;

a 5- to 6-membered heterocyclic radical unsubstituted or substituted byone or more C₁-C₂₀alkyl;

a C₁-C₂₀hydrocarbon radical containing one or more halogen; or

tri(C₁-C₁₀alkyl)silyl(C₁-C₁₀alkyl);

with the proviso that at least one of the radicals R₁, R₂ and R₃, or Y₁,Y₂ and Y₃, or Z₁, Z₂ and Z₃ is

branched C₃-C₂₀alkyl unsubstituted or substituted by one or morehydroxy;

C₂-C₂₀alkyl interrupted by oxygen or sulfur;

C₃-C₁₂cycloalkyl unsubstituted or substituted by one or moreC₁-C₂₀alkyl;

C₃-C₁₂cycloalkyl)-C₁-C₁₀alkyl unsubstituted or substituted by one ormore C_(l)-C₂₀alkyl;

a bicyclic or tricyclic hydrocarbon radical with 5 to 20 carbon atomsunsubstituted or substituted by one or more C₁-C₂₀alkyl;

phenyl unsubstituted or substituted by one or more radicals selectedfrom C₁-C₂₀alkyl, C₁-C₂₀alkoxy, C₁-C₂₀alkylamino, di(C₁-C₂₀alkyl)amino,hydroxy and nitro; phenyl-C₁-C₂₀alkyl unsubstituted or substituted byone or more radicals selected from C₁-C₂₀alkyl, C₃-C₁₂cycloalkyl,phenyl, C₁-C₂₀alkoxy and hydroxy; biphenyl-(C₁-C₁₀alkyl) unsubstitutedor substituted by one or more C₁-C₂₀alkyl; naphthyl-C₁-C₂₀alkylunsubstituted or substituted by one or more C₁-C₂₀alkyl; ortri(C₁-C₁₀alkyl)silyl(C₁-C₁₀alkyl).

According to a preferred embodiment, at least one of the radicals R₁, R₂and R₃, or Y₁, Y₂ and Y₃, or Z₁, Z₂ and Z₃ is branched C₃-C₂₀alkyl, orC₃-C₁₂cycloalkyl unsubstituted or substituted by one or moreC₁-C₂₀alkyl.

According to a particular preferred embodiment, at least one of theradicals R₁, R₂ and R₃, or Y₁, Y₂ and Y₃, or Z₁, Z₂ and Z₃ is branchedC₃-C₁₀alkyl.

Examples of C₁-C₂₀alkyl, e.g. branched C₃-C₂₀alkyl, unsubstituted orsubstituted by one or more hydroxy, e.g. 1, 2 or 3 hydroxy, are ethyl,n-propyl, 1-methylethyl, n-butyl, 2-methylpropyl, 1-methylpropyl,tert-butyl, pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl,1,1-dimethylpropyl, 1-ethylpropyl, tert-butylmethyl, hexyl,1-methylpentyl, heptyl, isoheptyl, 1-ethylhexyl, 2-ethylpentyl,1-propylbutyl, octyl, nonyl, isononyl, neononyl, 2,4,4-trimethylpentyl,undecyl, tridecyl, pentadecyl, heptadecyl, hydroxymethyl and1-hydroxyethyl. Branched C₃-C₁₀alkyl is particularly preferred. One ofthe preferred meanings of the radicals R₁, R₂ and R₃, or

Y₁, Y₂ and Y₃, or Z₁, Z₂ and Z₃ is branched C₃-C₁₀alkyl with aquaternary C atom in position 1, in particular —C(CH₃)₂—H or—C(CH₃)₂—(C₁-C₇alkyl).

Examples of C₂-C₂₀alkenyl unsubstituted or substituted by one or morehydroxy, e.g. 1, 2 or 3 hydroxy, are 9-decenyl, 8-heptadecenyl and11-hydroxy-8-heptadecenyl.

Examples of C₂-C₂₀alkyl interrupted by oxygen are t-butoxymethyl,t-butoxyethyl, t-butoxypropyl and t-butoxybutyl.

Examples of C₂-C₂₀alkyl interrupted by sulfur are (H₃C)₃C—S—CH₂—,(H₃C)₃C—S—C₂H₄—, (H₃C)₃C—S—C₃H₆— and (H₃C)₃C—S—C₄H₈—.

Examples of C₃-C₁₂cycloalkyl unsubstituted or substituted by one or moreC₁-C₂₀alkyl, e.g. 1, 2, 3 or 4 C₁-C₄alkyl, are cyclopropyl,3-methylcyclopropyl, 2,2,3,3-tetramethylcyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, 1-methylcyclohexyl, 2-methylcyclohexyl,3-methylcyclohexyl, 4-methylcyclohexyl, 4-tert-butylcyclohexyl andcycloheptyl.

Examples of (C₃-C₁₂cycloalkyl)-C₁-C₁₀alkyl unsubstituted or substitutedby one or more C₁-C₂₀alkyl, e.g. 1, 2 or 3 C₁-C₄alkyl, arecyclopentylmethyl, 2-cyclopentylethyl, cyclohexylmethyl,2-cycohexylethyl, 3-cyclohexylpropyl, 4-cyclohexylbutyl and(4-methylcyclohexyl)methyl.

An example of bis[C₃-C₁₂cycloalkyl]-C₁-C₁₀alkyl unsubstituted orsubstituted by one or more C₁-C₂₀alkyl, e.g. 1, 2 or 3 C₁-C₄alkyl, isdicyclohexylmethyl.

Examples of a bicyclic or tricyclic hydrocarbon radical with 5 to 20carbon atoms unsubstituted or substituted by one or more C₁-C₂₀alkyl,e.g. 1, 2 or 3 C₁-C₄alkyl, are

Examples of phenyl unsubstituted or substituted by one or more radicals,e.g. 1, 2 or 3 radicals, selected from C₁-C₂₀alkyl, C₁-C₂₀alkoxy,C₁-C₂₀alkylamino, di(C₁-C₂₀alkyl)amino, hydroxy and nitro, preferablyC₁-C₄alkyl, C₁-C₄alkoxy, C₁-C₄alkylamino, di(C₁-C₄alkyl)amino, hydroxyand nitro, are phenyl, 3-methylphenyl, 3-methoxyphenyl, 4-methylphenyl,4-ethylphenyl, 4-propylphenyl, 4-isopropylphenyl, 4-tert-butylphenyl,4-isopropoxyphenyl, 2,3-dimethoxyphenyl, 2-nitrophenyl,3-methyl-6-nitrophenyl, 4-dimethylaminophenyl, 2,3-dimethylphenyl,2,6-dimethylphenyl, 2,4-dimethylphenyl, 3,4-dimethylphenyl,3,5-dimethylphenyl, 3,5-di-tert-butylphenyl, 2,4,6-trimethylphenyl and3,5-di-tert-butyl-4-hydroxyphenyl.

Examples of phenyl-C₁-C₂₀alkyl unsubstituted or substituted by one ormore radicals, e.g. 1, 2 or 3 radicals, selected from C₁-C₂₀alkyl,C₃-C₁₂cycloalkyl, phenyl, C₁-C₂₀alkoxy and hydroxy, preferablyC₁-C₄alkyl, C₃-C₆cycloalkyl, phenyl, C₁-C₄alkoxy and hydroxy, arebenzyl, α-cyclohexyl benzyl, diphenylmethyl, 1-phenylethyl,α-hydroxybenzyl, 2-phenylethyl, 2-phenylpropyl, 3-phenylpropyl,3-methylbenzyl, 3,4-dimethoxybenzyl and 2-(3,4-dimethoxyphenyl)ethyl.

An example of phenylethenyl unsubstituted or substituted by one or moreC₁-C₂₀alkyl, e.g. 1, 2 or 3 C₁-C₄alkyl, is 2-(4-methylphenyl)ethenyl.

An example of biphenyl-(C₁-C₁₀alkyl) unsubstituted or substituted by oneor more C₁-C₂₀alkyl, e.g. 1, 2 or 3 C₁-C₄alkyl, is 4-biphenylmethyl.

Examples of naphthyl unsubstituted or substituted by one or moreC₁-C₂₀alkyl, e.g. 1, 2 or 3 C₁-C₄alkyl, are 1-naphthyl and 2-naphthyl.

Examples of naphthyl-C₁-C₂₀alkyl unsubstituted or substituted by one ormore C₁-C₂₀alkyl, e.g. 1, 2 or 3 C₁-C₄alkyl, are 1-naphthylmethyl and2-naphthylmethyl.

An example of naphthoxymethyl unsubstituted or substituted by one ormore C₁-C₂₀alkyl, e.g. 1, 2 or 3 C₁-C₄alkyl, is 1-naphthoxymethyl.

An examples of biphenylenyl, flourenyl or anthryl is 2-biphenylenyl,9-flourenyl, 1-flourenyl or 9-anthryl, respectively.

Examples of a 5- to 6-membered heterocyclic radical unsubstituted orsubstituted by one or more C₁-C₂₀alkyl, e.g. 1, 2 or 3 C₁-C₄alkyl, are3-pyridinyl, 4-pyridinyl, 2-hydroxypyridin-3-yl, 3-quinolinyl,4-quinolinyl, 2-furyl, 3-furyl and 1-methyl-2-pyrryl.

Examples of a C₁-C₂₀hydrocarbon radical containing one or more halogen,e.g. 1, 2, 3, 4, 5, or 6 —F, —Cl or -J, are 1-bromo-2-methylpropyl,dichloromethyl, pentafluoroethyl, 3,5-bis[trifluoromethyl]phenyl,2,3,5,6-tetrafluoro-p-tolyl, 2,3-dichlorophenyl, 3,4-dichlorophenyl and2,4-bis[trifluoromethyl]phenyl.

Examples of compounds of formula (IIa) are:

1,3,5-tris[cyclohexylcarbonylamino]benzene,

1,3,5-tris[2,2-dimethylpropionylamino]benzene,

1,3,5-tris[4-methylbenzoylamino]benzene,1,3,5-tris[3,4-dimethylbenzoylamino]benzene,

1,3,5-tris[3,5-dimethylbenzoylamino]benzene,

1,3,5-tris[cyclopentanecarbonylamino]benzene,

1,3,5-tris[1-adamantanecarbonylamino]benzene,

1,3,5-tris[2-methylpropionylamino]benzene,

1,3,5-tris[3,3-dimethylbutyrylamino]benzene,

1,3,5-tris[2-ethylbutyrylamino]benzene,

1,3,5-tris[2,2-dimethylbutyrylamino]benzene,

1,3,5-tris[2-cyclohexyl-acetylamino]benzene,

1,3,5-tris[3-cyclohexyl-propionylamino]benzene,

1,3,5-tris[4-cyclohexyl-butyrylamino]benzene,

1,3,5-tris[5-cyclohexyl-valeroylamino]benzene,

1-isobutyrylamino-3,5-bis[pivaloylamino]benzene,

2,2-dimethylbutyrylamino-3,5-bis[pivaloylamino]benzene,

3,3-dimethylbutyrylamino-3,5-bis[pivaloylamino]benzene,

1,3-bis[isobutyrylamino]-5-pivaloylaminobenzene,

1,3-bis[isobutyrylamino]-5-(2,2-dimethyl-butyryl)aminobenzene,

1,3-bis[isobutyrylamino]-5-(3,3-dimethyl-butyryl)aminobenzene,

1,3-bis[2,2-dimethylbutyrylamino]-5-pivaloylaminobenzene,

1,3-bis[2,2-dimethylbutyrylamino]-5-isobutyrylaminobenzene,

1,3-bis[2,2-dimethylbutyrylamino]-5-(3,3-dimethylbutyryl)-aminobenzene,

1,3-bis[3,3-dimethylbutyrylamino]-5-pivaloylamino-benzene,

1,3-bis[3,3-dimethylbutyrylamino]-5-isobutyryl-aminobenzene,

1,3-bis[3,3-dimethylbutyrylamino)-5-(2,2-dimethyl-butyrylamino)aminobenzene,and

1,3,5-tris[3-(trimethylsilyl)propionylamino]benzene.

Further examples of compounds of formula (IIa) are:

1,3,5-tris[2,2-dimethylvaleroylamino]benzene,

1,3,5-tris[3,3-dimethylvaleroylamino]benzene,

1,3,5-tris[2,4-dimethylvaleroylamino]benzene,

1,3,5-tris[4,4-dimethylvaleroylamino]benzene,

1,3,5-tris[4-methylvaleroylamino]benzene,

1,3,5-tris[2-methylbutyrylamino]benzene,

1,3,5-tris[2-methylvaleroylamino]benzene,

1,3,5-tris[3-methylvaleroylamino]benzene,

1,3,5-tris[2,2,3,3-tetramethyl-cyclopropanecarbonylamino]benzene,

1,3,5-tris[cyclopentylacetylamino]benzene,

1,3,5-tris[3-cyclopentylpropionylamino]benzene,

1,3,5-tris[2-norbornyl-acetylamino]benzene,

1,3,5-tris[4-t-butylcyclohexane-1-carbonylamino]benzene,

1,3,5-tris[2-(t-butoxy)-acetylamino]benzene,

1,3,5-tris[3-(t-butoxy)-propionylamino]benzene,

1,3,5-tris[4-(t-butoxy)-butyrylamino]benzene,

1,3,5-tris[5-t-butoxy-valeroylamino]benzene,

1,3,5-tris[cyclopropanecarbonylamino]benzene,

1,3,5-tris[2-methylcyclopropane-1-carbonylamino]benzene,

1,3,5-tris[3-noradamantane-1-carbonylamino]benzene,

1,3,5-tris[biphenyl-4-acetylamino]benzene,

1,3,5-tris[2-naphthyl-acetylamino]benzene,

1,3,5-tris[3-methylphenyl-acetylamino]benzene,

1,3,5-tris[(3,4-dimethoxyphenyl)-acetylamino]benzene,

1,3,5-tris[(3-trimethylsilyl-propionylamino]benzene, and

1,3,5-tris[(4-trimethylsilyl-butyrylamino]benzene.

Examples of compounds of formula (11b) are:

N-t-butyl-3,5-bis-(3-methylbutyrylamino)-benzamide,

N-t-butyl-3,5-bis-(pivaloylamino)-benzamide,

N-t-octyl-3,5-bis-(pivaloylamino)-benzamide,

N-(1,1-dimethyl-propyl)-3,5-bis-(pivaloylamino)-benzamide,

N-(t-octyl)-3,5-bis-(isobutyrylamino)-benzamide,

N-(t-butyl)-3,5-bis-(pivaloylamino)-benzamide,

N-(2,3-dimethyl-cyclohexyl)-3,5-bis-(pivaloylamino)-benzamide,

N-t-butyl-3,5-bis-(cyclopentanecarbonylamino)-benzamide,

N-(3-methylbutyl)-3,5-bis-(3-methylbutyrylamino)-benzamide,

N-(3-methylbutyl)-3,5-bis-(pivaloylamino)-benzamide,

N-(3-methylbutyl)-3,5-bis-(4-methylpentanoylamino)-benzamide,

N-(3-methylbutyl)-3,5-bis-(cyclopentanecarbonylamino)-benzamide,

N-(3-methylbutyl)-3,5-bis-(cyclohexanecarbonylamino)-benzamide,

N-cyclopentyl-3,5-bis-(3-methylbutyrylamino)-benzamide,

N-cyclopentyl-3,5-bis-(pivaloylamino)-benzamide,

N-cyclopentyl-3,5-bis-(4-methylpentanoylamino)-benzamide,

N-cyclopentyl-3,5-bis-(cyclopentanecarbonylamino)-benzamide,

N-cyclopentyl-3,5-bis-(cyclohexanecarbonylamino)-benzamide,

N-cyclohexyl-3,5-bis-(3-methylbutyrylamino)-benzamide,

N-cyclohexyl-3,5-bis-(pivaloylamino)-benzamide,

N-cyclohexyl-3,5-bis-(4-methylpentanoylamino)-benzamide,

N-cyclohexyl-3,5-bis-(cyclopentanecarbonylamino)-benzamide,

N-cyclohexyl-3,5-bis-(cyclohexanecarbonylamino)-benzamide,

N-isopropyl-3,5-bis-(pivaloylamino)-benzamide,

N-isopropyl-3,5-bis-(isobutyrylamino)-benzamide,

N-t-butyl-3,5-bis-(2,2-dimethylbutyrylamino)-benzamide, and

N-t-octyl-3,5-bis-(2,2-dimethylbutyrylamino)-benzamide.

Examples of compounds of formula (IIc) are:

5-pivaloylamino-isophthalic acid N,N′-di-t-butyldiamide,

5-pivaloylamino-isophthalic acid N,N′-di-t-octyldiamide,

5-(2,2-dimethylbutyrylamino)-isophthalic acid N,N′-di-t-butyldiamide,

5-(2,2-dimethylbutyrylamino)-isophthalic acid N,N′-di-t-octyldiamide,

5-(3-methylbutyrylamino)-isophthalic acid N,N′-di-cyclohexyldiamide,

5-(pivaloylamino)-isophthalic acid N,N′-di-cyclohexyldiamide,

5-(cyclopentanecarbonylamino)-isophthalic acidN,N′-di-cyclohexyldiamide,

5-(cyclohexylcarbonylamino)-isophthalic acid N,N′-di-cyclohexyldiamide,

5-(cyclopentanecarbonylamino)-isophthalic acidN,N′-bis-(2-methylcyclohexyl)diamide,

5-(cyclohexanecarbonylamino)-isophthalic acidN,N′-bis-(2-methylcyclohexyl)diamide,

5-((1-methylcyclohexanecarbonyl)amino)-isophthalic acidN,N′-bis-(2-methylcyclohexyl)diamide, and

5-((2-methylcyclohexanecarbonyl)amino)-isophthalic acidN,N′-bis-(2-methylcyclohexyl)diamide.

The addition of the aromatic trisamides to the thermoplastic polymer canbe carried out in all customary mixing machines in which the polymer ismelted and mixed with the additives.

Suitable machines are known to those skilled in the art. They arepredominantly mixers, kneaders and extruders.

The process is preferably carried out in an extruder by introducing theadditives during processing.

Particularly preferred processing machines are single-screw extruders,contrarotating and corotating twin-screw extruders, planetary-gearextruders, ring extruders or cokneaders. It is also possible to useprocessing machines provided with at least one gas removal compartmentto which a vacuum can be applied.

Suitable extruders and kneaders are described, for example, in Handbuchder Kunststoffextrusion, Vol. 1 Grundlagen, Editors F. Hensen, W.Knappe, H. Potente, 1989, pp. 3-7, ISBN:3-446-14339-4 (Vol. 2Extrusionsanlagen 1986, ISBN 3-446-14329-7).

For example, the screw length is 1-60 screw diameters, preferably 35-48screw diameters. The rotational speed of the screw is preferably 10-600rotations per minute (rpm), very particularly preferably 25-300 rpm.

The maximum throughput is dependent on the screw diameter, therotational speed and the driving force. The process of the presentinvention can also be carried out at a level lower than maximumthroughput by varying the parameters mentioned or employing weighingmachines delivering dosage amounts.

If a plurality of components are added, these can be premixed or addedindividually.

The polymers need to be subjected to an elevated temperature for asufficient period of time during incorporation of additives. Thetemperature is generally above the softening point of the polymers.

In a preferred embodiment of the processes of the present invention, atemperature range lower than 280° C., particularly from about 160° C. to280° C. is employed. In a particularly preferred process variant, thetemperature range from about 200° C. to 270° C. is employed.

In the processes and compositions of the present invention theabove-described aromatic trisamide compounds are present inconcentrations, based on the amount of the polymer, of from about 0.001to about 1.0% by weight. For instance, the trisamides are present fromabout 0.005 to 0.5% by weight, from about 0.01 to about 0.1% by weight,from about 0.01 to about 0.09% by weight, based on the weight of thepolymer. The aromatic trisamides can be added as individual compounds oras mixtures to the polymer.

Incorporation of additives into the polymers can be carried out, forexample, by mixing the above-described aromatic trisamides or mixturesthereof and, if desired, further additives into the polymers using themethods customary in process technology.

The aromatic trisamides can also be added to the polymers in the form ofa masterbatch in which these compounds are present, for example, in aconcentration of from about 1 to 25% by weight. The present inventiontherefore further provides a concentrate in which the compounds of theinvention are present in a concentration of 1-25% by weight and whichcan be added to the thermoplastic polymer.

Another aspect of this invention is that instead of melt blending, thepresent trisamides may be topically applied to the electret material.

For example in the case where the electret material is cotton thepresent trisamides may be topically applied.

Another aspect of this invention is the co-use of certain otheradditives along with the present aromatic trisamides. These certainother additives are incorporated in the same manner as the trisamides.

When employed without certain co-additives, the trisamides

are excluded from the present invention.

For instance, the class of stabilizers of the hindered amine lightstabilizers (HALS) are advantageously also employed in the presentcompositions and processes.

The present sterically hindered amine stabilizers contain at least onemoiety of formula

where G₁, G₂, G₃ and G₄ are independently alkyl of 1 to 8 carbon atomsor G₁ and G₂ or G₃ and G₄ together are pentamethylene and G₅ is hydrogenor alkyl of 1 to 8 carbon atoms.

The hindered amines are disclosed for example in U.S. Pat. Nos.5,004,770, 5,204,473, 5,096,950, 5,300,544, 5,112,890, 5,124,378,5,145,893, 5,216,156, 5,844,026, 5,980,783, 6,046,304, 6,117,995,6,271,377, 6,297,299, 6,392,041, 6,376,584, 6,472,456, and 7,030,196.The relevant disclosures of these patents are hereby incorporated byreference.

U.S. Pat. Nos. 6,271,377, 6,392,041 and 6,376,584, cited above disclosehindered hydroxyalkoxyamine stabilizers.

Suitable hindered amines include for example:

1) 1-cyclohexyloxy-2,2,6,6-tetramethyl-4-octadecylaminopiperidine,

2) bis(2,2,6,6-tetramethylpiperidin-4-yl)sebacate,

3) bis(1-acetoxy-2,2,6,6-tetramethylpiperidin-4-yl)sebacate,

4) bis(1,2,2,6,6-pentamethyl-4-yl)sebacate,

5) bis(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)sebacate,

6) bis(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl)sebacate;

7) bis(1-acyl-2,2,6,6-tetramethylpiperidin-4-yl)sebacate,

8)bis(1,2,2,6,6-pentamethyl-4-piperidyl)n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate

9)2,4-bis[(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)butylamino]-6-(2-hydroxy-ethylamino-s-triazine,

10) bis(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)adipate,

11)2,4-bis[(1-cyclohexyloxy-2,2,6,6-piperidin-4-yl)butylamino]-6-chloro-s-triazine,

12)1-(2-hydroxy-2-methylpropoxy)-4-hydroxy-2,2,6,6-tetramethylpiperidine,

13) 1-(2-hydroxy-2-methylpropoxy)-4-oxo-2,2,6,6-tetramethylpiperidine,

14)1-(2-hydroxy-2-methylpropoxy)-4-octadecanoyloxy-2,2,6,6-tetramethylpiperidine,

15) bis(1-(2-hydroxy-2-methylpropoxy)-2,2,6,6-tetramethylpiperidin-4-yl)sebacate,

16) bis(1-(2-hydroxy-2-methylpropoxy)-2,2,6,6-tetramethylpiperidin-4-yl)adipate,

17)2,4-bis{N41-(2-hydroxy-2-methylpropoxy)-2,2,6,6-tetramethylpiperidin-4-yl]-N-butyl-amino}-6-(2-hydroxyethylamino)-s-triazine,

18) 4-benzoyl-2,2,6,6-tetramethylpiperidine,

19)di-(1,2,2,6,6-pentamethylpiperidin-4-yl)p-methoxybenzylidenemalonate,

20) 4-stearyloxy-2,2,6,6-tetramethylpiperidine,

21) bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)succinate,

22) 1,2,2,6,6-pentamethyl-4-aminopiperidine,

23)2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxo-spiro[4,5]decane,

24) tris(2,2,6,6-tetramethyl-4-piperidyl)nitrilotriacetate,

25)tris(2-hydroxy-3-(amino-(2,2,6,6-tetramethylpiperidin-4-yl)propyl)nitrilotriacetate,

26)tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butane-tetracarboxylate,

27)tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,2,3,4-butane-tetracarboxylate,

28) 1,1′-(1,2-ethanediyl)-bis(3,3,5,5-tetramethylpiperazinone),

29) 3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decan-2,4-dione,

30)8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione,

31) 3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl)pyrrolidin-2,5-dione,

32)3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)pyrrolidine-2,5-dione,

33)N,N′-bis-formyl-N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine,

34) the reaction product of2,4-bis[(1-cyclohexyloxy-2,2,6,6-piperidin-4-yl)butylamino]-6-chloro-s-triazinewith N,N′-bis(3-aminopropyl)ethylenediamine),

35) the condensate of1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinicacid,

36) linear or cyclic condensates ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)-hexamethylenediamine and4-tert-octylamino-2,6-dichloro-1,3,5-triazine,

37) linear or cyclic condensates ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)-hexamethylenediamine and4-cyclohexylamino-2,6-dichloro-1,3,5-triazine,

38) linear or cyclic condensates ofN,N′-bis-(2,2,6,6-tetramethyl-4-piperidyl)-hexamethylenediamine and4-morpholino-2,6-dichloro-1,3,5-triazine,

39) linear or cyclic condensates ofN,N′-bis-(1,2,2,6,6-pentamethyl-4-piperidyl)-hexamethylenediamine and4-morpholino-2,6-dichloro-1,3,5-triazine,

40) the condensate of2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane,

41) the condensate of2-chloro-4,6-di-(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazineand 1,2-bis-(3-aminopropylamino)ethane,

42) a reaction product of7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro[4,5]decaneand epichlorohydrin,

43) poly[methyl,(3-oxy-(2,2,6,6-tetramethylpiperidin-4-yl)propyl)]siloxane, CAS #182635-99-0,

44) reaction product of maleic acid anhydride-C₁₈-C₂₂-α-olefin-copolymerwith 2,2,6,6-tetramethyl-4-aminopiperidine,

45) the oligomeric compound which is the condensation product of4,4′-hexamethylene-bis(amino-2,2,6,6-tetramethylpiperidine) and2,4-dichloro-6-[(2,2,6,6-tetramethylpiperidin-4-yl)butylamino]-s-triazineend-capped with 2-chloro-4,6-bis(dibutylamino)-s-triazine,

46) the oligomeric compound which is the condensation product of4,4′-hexamethylene-bis(amino-1,2,2,6,6-pentaamethylpiperidine) and2,4-dichloro-6-[(1,2,2,6,6-pentaamethyl-piperidin-4-yl)butylamino]-s-triazineend-capped with 2-chloro-4,6-bis(dibutylamino)-s-triazine,

47) the oligomeric compound which is the condensation product of4,4′-hexamethylene-bis(amino-1-propoxy-2,2,6,6-tetramethylpiperidine)and2,4-dichloro-6-[(1-propoxy-2,2,6,6-tetra-methylpiperidin-4-yl)butylamino]-s-triazineend-capped with 2-chloro-4,6-bis(dibutylamino)-s-triazine,

48) the oligomeric compound which is the condensation product of4,4′-hexamethylene-bis(amino-1-acyloxy-2,2,6,6-tetramethylpiperidine)and2,4-dichloro-6-[(1-acyloxy-2,2,6,6-tetra-methylpiperidin-4-yl)butylamino]-s-triazineend-capped with 2-chloro-4,6-bis(dibutylamino)-s-triazine and

49) product obtained by reacting a product, obtained by reacting1,2-bis(3-amino-propylamino)ethane with cyanuric chloride, with(2,2,6,6-tetramethylpiperidin-4-yl)butylamine.

Also included are the sterically hindered N—H, N-methyl, N-methoxy,N-propoxy, N-octyloxy, N-cyclohexyloxy, N-(2-hydroxy-2-methylpropoxy)and N-acyl analogues of any of the above mentioned compounds. Forexample, replacing an N—H hindered amine with an N-methyl hindered aminewould be employing the N-methyl analogue in place of the N—H.

The class of additives known as the hydroxyphenylalkylphosphonic estersor monoesters are also advantegously employed in the processes andcompositions of this invention. The hydroxyphenylalkylphosphonic estersor monoesters are disclosed for example in U.S. published app. No.2004/0106767, the disclosure of which is hereby incorporated byreference. The hydroxyphenylalkylphosphonic esters or monoesters are ofthe formula

wherein

R₆ is isopropyl, tert-butyl, cyclohexyl or cyclohexyl which issubstituted by 1-3 C₁-C₄alkyl groups,

R₇ is hydrogen, C₁-C₄alkyl, cyclohexyl or cyclohexyl which issubstituted by 1-3 C₁-C₄alkyl groups,

R₈ is C₁-C₂₀alkyl, unsubstituted or C₁-C₄alkyl-substituted phenyl ornaphthyl,

R₉ is hydrogen, C₁-C₂₀alkyl, unsubstituted or C₁-C₄alkyl-substitutedphenyl or naphthyl; or is

$\frac{M^{r +}}{r};$

M^(r+) is an r-valent metal cation,

p is 1, 2, 3, 4, 5 or 6, and

r is 1, 2 or 3.

For example, the present hydroxyphenylalkylphosphonic ester or monoesteris a compound of the formula P1 or P2

The further additives of the hindered amine light stabilizers and thehydroxyphenylalkylphosphonic esters or monoesters are employed atlevels, based on the weight of the polymer, of from about 0.001 to 5.0%by weight, in particular from 0.01 to 2.0% by weight and particularlypreferably from 0.02 to 1.0% by weight.

The following Examples further illustrate the invention. All percentagesare in weight percent unless otherwise indicated.

EXAMPLE 1

Polypropylene with MFI index of 1,100 is tumble mixed to contain 5.0%total weight of a sterically hindered amine (HALS), 2.0% total weight ofa sterically hindered hydroxyphenylalkylphosphonic monoester (HPPME),0.25% total weight aromatic trisamide (TA1)-(TA14).

These mixes are individually compounded using a Leistritz 27 mm twinscrew extruder. The melt is cooled in a water trough and the strand isconverted into pellets via a Conair-Jetro Model 304 pelletizer. Thepellets collected are considered the masterbatches.

The same polypropylene is tumble mixed with the appropriate amounts ofmasterbatch for each of the evaluations. The tumble mixing is via aMarion Mixer SPS 1224 which is a paddle type slow RPM mixer. These areconsidered the final mixes.

Final mixes at 45 Kg each are converted into melt blown non woventextiles using a 500 mm Reifenhauser Meltblowing Pilot Line. Also a1,500 g portion of each final mix is processed on a 6-inch MeltblowingPilot Line.

The polypropylene webs are then treated by corona discharge. The samplesare tested using TSI Filter Tester (Model 8130) which employs challengesof sodium chloride aerosol at 32 liters per minute using a test area of100 cm².

Results are in the tables below.

TABLE 1 6-inch Meltblowing Pilot Line Filtration Efficiency (%) BasisCharged & Filtration Weight Before After aged (70° C./24 EfficiencyFormulation (g/m²) charging charging hrs) Loss (%) Polypropylene 30.623.2 88.0 72.4 17.7 (control)  0.5% HALS 30.5 16.8 91.5 82.1 10.2  0.5%HPPME 30.6 18.7 93.3 90.6  2.9 0.05% TA1 30.4 18.0 93.4 93.3  0.1 0.02%TA2 30.5 18.3 92.2 91.3  0.9

TABLE 2 6-inch Meltblowing Pilot Line Filtration Efficiency (%) BasisCharged & Filtration Weight Before After aged (70° C./24 EfficiencyFormulation (g/m²) charging charging hrs) Loss (%) Polypropylene 58.334.6 96.9 90.6 6.4 (control)  0.5% HALS 60.4 32.8 99.0 97.0 2.0  0.5%HPPME 59.2 31.4 98.9 97.7 1.2 0.05% TA1 58.0 31.9 99.0 98.5 0.5 0.02%TA2 60.9 44.5 98.4 97.4 1.0

TABLE 3 500 mm Reifenhäuser Meltblowing Pilot Line Filtration Efficiency(%) Basis Charged & Filtration Weight Before After aged (70° C./24Efficiency Formulation (g/m²) charging charging hrs) Loss (%)Polypropylene 30.6 17.0 81.4 65.6 19.4 (control)  0.5% HALS 30.5 15.890.0 85.4 5.1  0.5% HPPME 30.6 16.8 90.4 86.8 4.0 0.05% TA1 30.4 16.292.1 90.8 1.4 0.02% TA2 30.5 13.8 90.4 88.0 2.8

TABLE 4 500 mm Reifenhäuser Meltblowing Pilot Line Filtration Efficiency(%) Basis Charged & Filtration Weight Before After aged (70° C./24Efficiency Formulation (g/m²) charging charging hrs) Loss (%)Polypropylene 58.3 28.0 94.7 78.4 17.2 (control)  0.5% HALS 60.4 29.496.6 90.2 6.6  0.5% HPPME 59.2 27.4 94.8 92.6 2.2 0.05% TA1 58.0 28.495.8 94.8 1.0 0.02% TA2 60.9 26.6 93.4 91.8 1.7

TABLE 5 PP 6-inch Meltblowing Pilot Line Filtration Efficiency (%) BasisCharged & Filtration Weight Before After aged (70° C./24 EfficiencyFormulation (g/m²) charging charging hrs) Loss (%) Polypropylene 30.922.2 85.6 67.7 20.9 (control)  0.5% HALS 30.5 24.4 91.2 78.9 13.5 0.025%TA3 29.4 32.7 92.8 80.7 13.1 0.025% TA4 27.8 22.8 92.7 86.0 7.2 0.025%TA5 27.5 24.0 90.5 79.5 12.2 0.025% TA6 29.3 31.2 93.3 81.4 12.7

TABLE 6 PP 6-inch Meltblowing Pilot Line Filtration Efficiency (%) BasisCharged & Filtration Weight Before After aged (70° C./24 EfficiencyFormulation (g/m²) charging charging hrs) Loss (%) Polypropylene 30.117.0 86.7 60.9 29.8 (control)   0.5% HALS 29.1 15.2 88.7 68.3 23.00.0125% TA7 29.5 11.6 80.5 63.4 21.3 0.0125% TA4 29.0 11.7 81.2 68.016.3

TABLE 7 6-inch Meltblowing Pilot Line Filtration Efficiency (%) BasisCharged & Filtration Weight Before After aged (70° C./24 EfficiencyFormulation (g/m²) charging charging hrs) Loss (%) Polypropylene 29.620.5 76.1 54.9 27.9 (control)  0.5% HALS 29.2 17.9 84.0 66.6 20.7 0.02%TA8 27.2 21.6 90.9 84.7 6.9 0.02% TA9 28.6 22.8 91.2 83.0 9.0 0.02% TA1028.2 23.1 88.4 70.6 20.1 0.02% TA11 29.3 20.7 88.9 74.5 16.2 0.02% TA1229.1 21.5 89.8 78.7 12.4 0.02% TA13 27.7 21.9 89.9 77.0 14.4

TABLE 8 6-inch Meltblowing Pilot Line Filtration Efficiency (%) BasisCharged & Filtration Weight Before After aged (70° C./24 EfficiencyFormulation (g/m²) charging charging hrs) Loss (%) Polypropylene 29.620.5 76.1 54.9 27.9 (control)  0.5% HALS 29.2 17.9 84.0 66.6 20.7  0.5%HPPME 30.6 21.4 88.7 74.6 15.9 0.02% TA8 27.2 19.9 87.2 83.4 4.4 0.02%TA10 27.5 16.1 82.4 77.3 6.2

It can be seen that the present aromatic trisamides providepolypropylene with excellent thermal and charge stability. Thetrisamides are present at very low levels.

1. An electret material with enhanced thermal and charge stability,which material has been subjected to an electret treatment, comprising athermoplastic polymer and incorporated therein, one or more aromatictrisamide compounds of formula I

wherein R₁, R₂, R₃, R₄, R₅ and R₆, independently of one another, arehydrogen, C₁-C₂₀alkyl, C₂-C₂₀alkyl substituted by C₁-C₁₀alkylamino,di(C₁-C₁₀alkyl)amino, C₁-C₁₀alkyloxy or hydroxy; C₃-C₂₀alkenyl,C₅-C₁₂cycloalkyl, C₅-C₁₂cycloalkyl substituted by 1, 2 or 3 C₁-C₁₀alkyl;cyclohexylmethyl; cyclohexylmethyl substituted by 1, 2 or 3 C₁-C₁₀alkyl;C₅-C₉cycloalkenyl, C₅-C₉cycloalkenyl substituted by 1, 2 or 3C₁-C₁₀alkyl; phenyl substituted by 1, 2 or 3 radicals selected from thegroup consisting of C₁-C₁₀alkyl, C₁-C₁₀alkyloxy, hydroxy, halogen,trihalogenmethyl, trihalogenmethoxy, benzoyl, phenylamino, acylamino andphenylazo; C₇-C₉phenylalkyl, C₇-C₉phenylalkyl which is substituted onthe phenyl by 1, 2 or 3 radicals selected from the group consisting ofC₁-C₁₀alkyl, C₁-C₁₀alkoxy and hydroxy; naphthyl, naphthyl substituted byC₁-C₁₀alkyl; adamantyl, or a 5 to 6 membered heterocyclic group; or oneor more aromatic trisamide compounds of the formula IIa, IIb or IIc

wherein R₁, R₂ and R₃, or Y₁, Y₂ and Y₃, or Z₁, Z₂ and Z₃ independentlyof one another are C₁-C₂₀alkyl unsubstituted or substituted by one ormore hydroxy; C₂-C₂₀alkenyl unsubstituted or substituted by one or morehydroxy; C₂-C₂₀alkyl interrupted by oxygen or sulfur; C₃-C₁₂cycloalkylunsubstituted or substituted by one or more C₁-C₂₀alkyl;(C₃-C₁₂cycloalkyl)-C₁-C₁₀alkyl unsubstituted or substituted by one ormore C_(l)-C₂₀alkyl; bis[C₃-C₁₂cycloalkyl]-C₁-C₁₀alkyl unsubstituted orsubstituted by one or more C₁-C₂₀alkyl; a bicyclic or tricyclichydrocarbon radical with 5 to 20 carbon atoms unsubstituted orsubstituted by one or more C₁-C₂₀alkyl; phenyl unsubstituted orsubstituted by one or more radicals selected from C₁-C₂₀alkyl,C₁-C₂₀alkoxy, C₁-C₂₀alkylamino, di(C₁-C₂₀alkyl)amino, hydroxy and nitro;phenyl-C₁-C₂₀alkyl unsubstituted or substituted by one or more radicalsselected from C₁-C₂₀alkyl, C₃-C₁₂cycloalkyl, phenyl, C₁-C₂₀alkoxy andhydroxy; phenylethenyl unsubstituted or substituted by one or moreC₁-C₂₀alkyl; biphenyl-(C₁-C₁₀alkyl) unsubstituted or substituted by oneor more C₁-C₂₀alkyl; naphthyl unsubstituted or substituted by one ormore C₁-C₂₀alkyl; naphthyl-C₁-C₂₀alkyl unsubstituted or substituted byone or more C₁-C₂₀alkyl; naphthoxymethyl unsubstituted or substituted byone or more C₁-C₂₀alkyl; biphenylenyl, flourenyl, anthryl; a 5- to6-membered heterocyclic radical unsubstituted or substituted by one ormore C₁-C₂₀alkyl; a C₁-C₂₀hydrocarbon radical containing one or morehalogen; or tri(C₁-C₁₀alkyl)silyl(C₁-C₁₀alkyl); with the proviso that atleast one of the radicals selected from R₁, R₂ and R₃, or Y₁, Y₂ and Y₃,or Z₁, Z₂ and Z₃ is branched C₃-C₂₀alkyl unsubstituted or substituted byone or more hydroxy; C₂-C₂₀alkyl interrupted by oxygen or sulfur;C₃-C₁₂cycloalkyl unsubstituted or substituted by one or moreC₁-C₂₀alkyl; (C₃-C₁₂cycloalkyl)-C₁-C₁₀alkyl unsubstituted or substitutedby one or more C_(l)-C₂₀alkyl; a bicyclic or tricyclic hydrocarbonradical with 5 to 20 carbon atoms unsubstituted or substituted by one ormore C₁-C₂₀alkyl; phenyl unsubstituted or substituted by one or moreradicals selected from C₁-C₂₀alkyl, C₁-C₂₀alkoxy, C₁-C₂₀alkylamino,di(C₁-C₂₀alkyl)amino, hydroxy and nitro; phenyl-C₁-C₂₀alkylunsubstituted or substituted by one or more radicals selected fromC₁-C₂₀alkyl, C₃-C₁₂cycloalkyl, phenyl, C₁-C₂₀alkoxy and hydroxy;biphenyl-(C₁-C₁₀alkyl) unsubstituted or substituted by one or moreC₁-C₂₀alkyl; naphthyl-C₁-C₂₀alkyl unsubstituted or substituted by one ormore C₁-C₂₀alkyl; or tri(C₁-C₁₀alkyl)silyl(C₁-C₁₀alkyl), where thearomatic trisamide compounds are present from about 0.005 to 0.5% byweight, based on the weight of the thermoplastic polymer and where thethermoplastic polymer further has incorporated therein an additiveselected from the group consisting of hydroxyphenylalkylphosphonicesters or monoesters and hindered amine light stabilizers.
 2. Anelectret material according to claim 1 comprising one or more trisamidecompounds of formula I.
 3. An electret material according to claim 1comprising one or more trisamide compounds of formula IIa, IIb or IIc.4. An electret material according to claim 1 in which the thermoplasticpolymer is polypropylene.
 5. An electret material according to claim 1in which the thermoplastic polymer is a nonwoven polypropylene web. 6.An electret material according to claim 1 where in the compounds offormula IIa, IIb and IIc, that at least one of the radicals selectedfrom R₁, R₂ and R₃, or Y₁, Y₂ and Y₃, or Z₁, Z₂ and Z₃ is branchedC₃-C₂₀alkyl, or is C₃-C₁₂cycloalkyl unsubstituted or substituted by oneor more C₁-C₂₀alkyl.
 7. An electret material according to claim 1 wherethe electret treatment is a corona treatment.
 8. An electret materialaccording to claim 1 wherein the thermoplastic polymer further hasincorporated therein an additive selected from the group consisting ofthe hindered amine light stabilizers.
 9. An electret material accordingto claim 1 wherein the thermoplastic polymer further has incorporatedtherein an additive selected from the group consisting of thehydroxyphenylalkylphosphonic esters or monoesters.
 10. An electretmaterial according to claim 1 wherein the aromatic trisamide compoundsare present from about 0.01 to about 0.09% by weight, based on theweight of the thermoplastic polymer.
 11. A method for preparing anelectret material with enhanced thermal and charge stability, whichmethod comprises melt blending a thermoplastic polymer with one or morearomatic trisamide compounds of formula I

wherein R₁, R₂ and R₃, independently of one another, are C₁-C₂₀alkyl,C₂-C₂₀alkyl substituted by C₁-C₁₀alkylamino, di(C₁-C₁₀alkyl)amino,C₁-C₁₀alkyloxy or hydroxy; C₃-C₂₀alkenyl, C₅-C₁₂cycloalkyl,C₅-C₁₂cycloalkyl substituted by 1, 2 or 3 C₁-C₁₀alkyl; cyclohexylmethyl;cyclohexylmethyl substituted by 1, 2 or 3 C₁-C₁₀alkyl;C₅-C₉cycloalkenyl, C₅-C₉cycloalkenyl substituted by 1, 2 or 3C₁-C₁₀alkyl; phenyl substituted by 1, 2 or 3 radicals selected from thegroup consisting of C₁-C₁₀alkyl, C₁-C₁₀alkyloxy, hydroxy, halogen,trihalogenmethyl, trihalogenmethoxy, benzoyl, phenylamino, acylamino andphenylazo; C₇-C₉phenylalkyl, C₇-C₉phenylalkyl which is substituted onthe phenyl by 1, 2 or 3 radicals selected from the group consisting ofC₁-C₁₀alkyl, C₁-C₁₀alkoxy and hydroxy; naphthyl, naphthyl substituted byC₁-C₁₀alkyl; adamantyl, or a 5 to 6 membered heterocyclic group; or oneor more aromatic trisamide compounds of formula IIa, IIb or IIc

wherein R₁, R₂ and R₃, or Y₁, Y₂ and Y₃, or Z₁, Z₂ and Z₃ independentlyof one another are C₁-C₂₀alkyl unsubstituted or substituted by one ormore hydroxy; C₂-C₂₀alkenyl unsubstituted or substituted by one or morehydroxy; C₂-C₂₀alkyl interrupted by oxygen or sulfur; C₃-C₁₂cycloalkylunsubstituted or substituted by one or more C₁-C₂₀alkyl;(C₃-C₁₂cycloalkyl)-C₁-C₁₀alkyl unsubstituted or substituted by one ormore C₁-C₂₀alkyl; bis[C₃-C₁₂cycloalkyl]-C₁-C₁₀alkyl unsubstituted orsubstituted by one or more C₁-C₂₀alkyl; a bicyclic or tricyclichydrocarbon radical with 5 to 20 carbon atoms unsubstituted orsubstituted by one or more C₁-C₂₀alkyl; phenyl unsubstituted orsubstituted by one or more radicals selected from C₁-C₂₀alkyl,C₁-C₂₀alkoxy, C₁-C₂₀alkylamino, di(C₁-C₂₀alkyl)amino, hydroxy and nitro;phenyl-C₁-C₂₀alkyl unsubstituted or substituted by one or more radicalsselected from C₁-C₂₀alkyl, C₃-C₁₂cycloalkyl, phenyl, C₁-C₂₀alkoxy andhydroxy; phenylethenyl unsubstituted or substituted by one or moreC₁-C₂₀alkyl; biphenyl-(C₁-C₁₀alkyl) unsubstituted or substituted by oneor more C₁-C₂₀alkyl; naphthyl unsubstituted or substituted by one ormore C₁-C₂₀alkyl; naphthyl-C₁-C₂₀alkyl unsubstituted or substituted byone or more C₁-C₂₀alkyl; naphthoxymethyl unsubstituted or substituted byone or more C₁-C₂₀alkyl; biphenylenyl, flourenyl, anthryl; a 5- to6-membered heterocyclic radical unsubstituted or substituted by one ormore C₁-C₂₀alkyl; a C₁-C₂₀hydrocarbon radical containing one or morehalogen; or tri(C₁-C₁₀alkyl)silyl(C₁-C₁₀alkyl); with the proviso that atleast one of the radicals selected from R₁, R₂ and R₃, or Y₁, Y₂ and Y₃,or Z₁, Z₂ and Z₃ is branched C₃-C₂₀alkyl unsubstituted or substituted byone or more hydroxy; C₂-C₂₀alkyl interrupted by oxygen or sulfur;C₃-C₁₂cycloalkyl unsubstituted or substituted by one or moreC₁-C₂₀alkyl; (C₃-C₁₂cycloalkyl)-C₁-C₁₀alkyl unsubstituted or substitutedby one or more C_(l)-C₂₀alkyl; a bicyclic or tricyclic hydrocarbonradical with 5 to 20 carbon atoms unsubstituted or substituted by one ormore C₁-C₂₀alkyl; phenyl unsubstituted or substituted by one or moreradicals selected from C₁-C₂₀alkyl, C₁-C₂₀alkoxy, C₁-C₂₀alkylamino,di(C₁-C₂₀alkyl)amino, hydroxy and nitro; phenyl-C₁-C₂₀alkylunsubstituted or substituted by one or more radicals selected fromC₁-C₂₀alkyl, C₃-C₁₂cycloalkyl, phenyl, C₁-C₂₀alkoxy and hydroxy;biphenyl-(C₁-C₁₀alkyl) unsubstituted or substituted by one or moreC₁-C₂₀alkyl; naphthyl-C₁-C₂₀alkyl unsubstituted or substituted by one ormore C₁-C₂₀alkyl; or tri(C₁-C₁₀alkyl)silyl(C₁-C₁₀alkyl) and subjectingthe blend to an electret treatment, where the aromatic trisamidecompounds are present from about 0.005 to 0.5% by weight, based on theweight of the thermoplastic polymer and melt blending the thermoplasticpolymer with a further additive selected from the group consisting ofhydroxyphenylalkylphosphonic esters or monoesters and hindered aminelight stabilizers.
 12. A method according to claim 11 comprising meltblending the thermoplastic polymer with one or more trisamide compoundsof formula I.
 13. A method according to claim 11 comprising meltblending the thermoplastic polymer with one or more trisamide compoundsof formula IIa, IIb or IIc.
 14. A method according to claim 11 in whichthe thermoplastic polymer is polypropylene.
 15. A method according toclaim 11 in which the blend is a nonwoven polypropylene web.
 16. Amethod according to claim 11 where in the compounds of formula IIa, IIband IIc, at least one of the radicals selected from R₁, R₂ and R₃, orY₁, Y₂ and Y₃, or Z₁, Z₂ and Z₃ is branched C₃-C₂₀alkyl, or isC₃-C₁₂cycloalkyl unsubstituted or substituted by one or moreC₁-C₂₀alkyl.
 17. A method according to claim 11 where the electrettreatment is a corona treatment.
 18. A method according to claim 11which comprises melt blending the thermoplastic polymer with a furtheradditive selected from the group consisting of the hindered amine lightstabilizers.
 19. A method according to claim 11 which comprises meltblending the thermoplastic polymer with a further additive selected fromthe group consisting of the hydroxyphenylalkylphosphonic esters ormonoesters.
 20. A method according to claim 11 where the aromatictrisamides are present from about 0.01 to about 0.09% by weight, basedon the weight of the thermoplastic polymer.
 21. An electret materialaccording to claim 1 which is in the form of a nonwoven fibrous web. 22.A method according to claim 11, which method further comprisesconverting the melt blend to a nonwoven fibrous web.